add core installer to allow plugins

Update core to 6, add allow-plugins config

Update composer.json

Update WP core to 5.0

Merge branch 'master' of https://github.com/wodby/wordpress-composer

Merge pull request #9 from mantis4444/formatting-fix

Fixed formatting

Merge pull request #4 from leymannx/patch-10

Update README.md

Merge remote-tracking branch 'origin/master'

Merge remote-tracking branch 'origin/master'

Freeze wordpress core to ~4.9

Update composer.json

Update script for WP stack 4.x

Add stub preserve paths